Classification

Distribution

Considered endemic to the section of the Mekong river basin which flows through northern Laos before forming the border with Thailand and eventually entering Cambodia just below the Khone Pha Pheng falls. It’s distribution thus overlaps that of its widespread congener H. macrolepidota.

Type locality is ‘Monam Mun at Udon, Thailand’, which appears to correspond to the lower section of the Mun River, a tributary which joins the Mekong in Ubon Ratchathani province, eastern Thailand.

Habitat

Predominantly a riverine fish preferring clear, well-oxygenated, running water with substrates of sand, gravel, rock or mud although it is adaptable and can be found in both upland and lowland, standing or flowing waters.

During the rainy season it is known to migrate into areas of inundated forest to feed and spawn, and can now be found in many impounded water bodies as a result of human activity such as agriculture and damming of river channels.

Maximum Standard Length

An active, pelagic species requiring an aquarium with base dimensions of 240 ∗ 60 cm or more for long-term care.

Maintenance

Choice of décor is not as critical as water quality and the amount of open swimming-space provided. However should you possess the means to both provide and decorate a sufficiently-sized aquarium this species a set-up designed to resemble a flowing river with a substrate of variably-sized rocks and gravel, some large water-worn boulders and perhaps a couple of driftwood branches is recommended.

Like many fishes that naturally inhabit running waters it’s intolerant to the accumulation of organic wastes and requires spotless water at all times in order to thrive. It also does best if there is a high level of dissolved oxygen and a decent level of water movement in the tank so external filters, powerheads, etc., should be employed in order to obtain the desired effect.

Be sure to fit the aquarium with a heavy, tightly-fitting cover as larger cyprinids can be quite skittish at times and usually possess a powerful leap.

Water Conditions

Diet

Predatory with a capacious mouth. Stomach analyses of wild specimens from Cambodia have shown it to feed chiefly on crabs, shrimp and insects with some smaller fish also taken. In the aquarium it will accept dried foods but should not be fed these exclusively with daily meals of live and frozen foods key to keeping it in the best of health.

Smaller specimens can be offered bloodworm, small earthworms, chopped prawn and suchlike while adults will take whole prawns, larger earthworms, mussels, whitebait, etc. Take care not to overfeed as it will gorge itself given the opportunity.

It should not be fed large amounts of mammalian/avian meat such as beef heart or chicken. Some of the lipids contained in these meats cannot be properly metabolised by the fish and can cause excess deposits of fat and even organ degeneration. Similarly there is no benefit in the use of ‘feeder’ fish such as livebearers or small goldfish which carry with them associated risks such as the introduction of parasites or disease.

Hampala spp. are voracious feeders especially when maintained in numbers. Some aquarists have observed that the ‘alpha’ individual in a group will lead the others in a pack-style behaviour, and anglers’ reports state that the water surface will literally boil when a shoal is feeding. So enthusiastically does it attack food that it’s sometimes recommended as a useful tankmate for fastidious or newly-introduced fishes that are refusing to eat.

Captures its prey using suction rather than aggressively biting and otherwise peaceful with anything it can’t swallow, although its speed of movement and feeding habits suggest that slow-moving or timid tankmates would probably be out competed. Smaller specimens are easy to maintain alongside other species but as they grow become increasingly powerful and domineering when food is available meaning companions must be chosen with care.

Similarly-sized cyprinids, characids, catfishes and larger botiid loaches perhaps constitute the best choices. A large Mekong-themed community could be an interesting project with options including Barbonymus, Cyclocheilichthys, Osteochilus, and Hypsibarbus wetmorei species among many others.

Though gregarious by nature it is a shoaling rather than schooling species which develops a distinct pecking order and therefore should always be maintained in a group of five or more. If only two or three are present the subdominant fish may be subjected to excessive antagonism whereas solitary specimens tend to act rather nervously.

Sexual Dimorphism

Reproduction

Although it needs plenty of space H. dispar makes a more suitable aquarium resident than the more commonly-traded congener H. macrolepidota due to its significantly smaller adult size.

The genus Hampala currently contains seven species of which H. macrolepidota and, to a lesser extent, H. dispar are the only ones seen with any regularity in the aquarium trade. As well as being the more widely-distributed in nature, H. macrolepidota is also the largest of the group. All representatives can appear superficially similar at first glance, the exception being H. lopezi which is endemic to a single island in The Philippines and displays a unique lateral band-like marking on the flanks.

H. macrolepidota is easy to identify by colour pattern, which comprises a dark vertical band originating anterior to the dorsal-fin and extending below the lateral line, plus the presence of black marginal stripes in both lobes of the caudal-fin. H. dispar possesses only a single dark blotch-like marking on the body and has less well-defined marginal stripes on the caudal lobes.

Juveniles of the two species can appear very similar as the body blotch is extended vertically in young H. dispar, plus both display a broadish dark band across the caudal peduncle, a second, thinner band across the base of the caudal-fin, and a small blotch above the anal-fin. All of these markings are less intense in H. dispar while in H. macrolepidota there is additional dark patterning above and below the eye and running downwards from the nape to the pelvic fins.

H. sabana also has a single body marking but a higher count of circumpeduncular scales (30-32) and relatively few lateral line scales (12-15) compared to its congeners. H. ampalong, H. bimaculata and H. salweenensis can be trickier to separate since they all have two body blotches. H. ampalong possesses more lateral line scales than H. salweenensis (28-31 vs. 26-27) whereas in H. bimaculata the body markings are saddle-shaped and the anterior blotch is positioned underneath the posterior half of the dorsal-fin (below the dorsal-fin origin in the other two).

It is worth noting that the body markings tend to fade in very large specimens of all Hampala spp., and it’s possible that additional species will be described in the future as a phylogenetic study published in 2006 concluded that the form of H. bimaculata from central and southern parts of the Malaysian state of Sarawak, Borneo ought to be considered distinct, for example.

Kottelat, M., 2013 - Raffles Bulletin of Zoology Supplement 27: 1-663The fishes of the inland waters of southeast Asia: a catalogue and core bibiography of the fishes known to occur in freshwaters, mangroves and estuaries.